Process of manufacturing soap



Patented July 20, 1937 UNITED STATES PATENT OFFICE 2,087,267 PROCESS OFMANUFACTURING SOAP Julius Schaal, New York, N. Y.

No Drawing. Application May No. 22,557. In Germany December 21, 1935,Serial 1 Claim. (01. 87-16) In order to expedite the reaction, a smallMy invention relates to soap manufacture and has for its object todevise a new process whereby soap can be made with a minimum expenditureof time, labor and, expense.

and pressed require again from one to two days.

Moreover,- this method, besides being slow, requires the' installationof a heating plant or steam-boiler, large boiling kettles, cooling de-:vices, drying apparatus, pumps etc. necessitatstituents used,'i. e.,the fats ing large buildings with sufiicient floor-space. Also largeamounts of fuel, water and salts must be on hand, all of which requireslarge working capital. v

My new process of making soap does away with all these expensiveinstallations, apparatus etc. and permits the manufacture of soap in afraction of the time and with a fraction of the expense required by theordinary soap-making process. According to the present method, thesaponiflcation is efiected without the supply of any outside heat,either direct or indirect. The fats or oils, both of animal andvegetable origin, are

merely heated to a temperature somewhat higher than their melting point.previously dissolved in water have been added, there occurs after abrief period of time, 10 to 20 minutes, the reactiom'and the heatgenerated thereby is quite sufllci f t, to heat the entire mass to atemperature of to C. resulting in an Then, when the alkalis intenseboiling of the In my process only enough water is used as is requiredfor the saponifying operation to produce a homogeneous plastic soapbody.

One of the conditions for the successful-practice of my new process isthe maintenance of definite temperatures of the mixtures offats and thealkali solutions and the observation of certain procedures in the mixingtogether of the conand alkalis.

I have found that only with a quite definite percentage of the alkalisolutions used in my process a complete saponification takes place. whensaponifleation is effected with sodium oxid'e (NaOH) the percentage is40%, while in the case of saponiflcation with caustic potash (KOH) thepercentage is 49% (determined according to the specific weight at 15 C.)

any bleaching action.

about 30-60 minutes, elapse quality of the fats (neutral fats containingas and 50 kilograms of cocoanut amount (V of hydrogen peroxide (30%) isadded to the mixture of fats and oils prior to the admixture of thealkalis. There is hardly From the time the constituents are mixedtogether until the finished complete saponification depending on themuchas 10% free fatty acid can be used) and the amount of the charge. Atthis time of the process, corrections can be made, that is to say, thealkalinity can be increased or decreased, the water content can bemodified, and other ingredients, e. g. calcined soda, silicate, borax,tri-- sodiumphosphate, medicaments, perfumes, pigments, etc. can beadded. With my saponlflcation method, also a good floating soap can beproduced. The process can be carried out in any suitable mixing troughor good stirring apparatus. passed over cooling rolls and is then readyfor any further treatment depending on the kind of soap desired, whetherin the shape of bars, cakes, flakes, powder, etc. Since the glycerinremains in the soap, the soap can be advantageously used as a cosmeticsoap. Instead of the soap being passed over cooling rolls, it can alsobe cast into molds or spread on a clean concrete floor. Any waste isreturned to the kettle wherein the saponification is effected. a

- The following is an example of my new process for making a soapsuitable for the manufacture of a toilet-soap.

1. 200 kilograms of beef-tallow (titre 40-41) oil are carefully weighedand are melted at a temperature of 50-52 C.

2. 38.65 kilograms of caustic soda (128-130), in the shape of scales orflakes, are dissolved in 40 kilograms of water. The dissolving operationgenerates a temperature of about 95 C.) The solution is left standingfor about ten minutes. A light-layer of dirt collects on the surface,which layer is removed.

3. 8 kilograms of water, dium or potassium silicate and about 1 kilogramThe finished soap is of the above alkali solution are mixed togetherenamelled vessel 5 kilograms of st.

kettle equipped with a I having a temperature of 50 to 52 C. is pouredgrams of water, and this small amount of soluthrough a fine cloth intothe kettle, and the stirtion is stirred for about five minutes into thesoap ring apparatus therein is started. Thereupon, mass. If upon anothertest the pink color does 1% kilograms of hydrogen peroxide and then thealkali solution having a temperature of to 92 C. are poured into thekettle. The stirring apparatus is permitted to operate, until theemulsion commences to thicken, which will occur after about 5 to 10minutes, when the stirring apparatus is immediately stopped". Afterabout 2 minutes, the mass in the kettle becomes stiff, and now commencesthe saponification. The temperature gradually rises inabout 8 to 10minutes from about 60 to C., at which temperature the surface commencesto rise. When it ruptures, there follows an intense boiling accompaniedby a rising of the mass, the temperature increasing to from about to C.The

reaction is permitted to continue, until the entire kettle is completelystirring apparatus is set in operation for a short period to cause abreaking down of the boiling mass, whereupon the stirring apparatus isimmediately stopped again, to prevent the reaction from beinginterrupted. The rising of the mass in the kettle will be repeatedabout5 or 6 times, and each time, the stirring apparatus is set in operationfor a brief period to prevent the mass from boiling over. Only after thereaction has come to a complete stop, the stirring apparatus ispermitted to operate for about five minutes more to produce a thoroughmixture of the constituents. It is very important not to prematurelyinterrupt the reaction by the operation of the stirring apparatus,because otherwise the genera-' tion of the heat in the mass and completesaponification would thereby be prevented.

After the mass has been stirred for about five minutes, it is uniformlyhomogeneous and rather thick. The stirring is then stopped for a whileto permit all soap portions spattered on the walls of the container tobe scraped ofl. Thereupon, the stirring apparatus is started again, andthe above mentioned solution of silicate and water, which must have atemperature of at least 90 C. is then very slowly added to the mass. Thelatter again commences to rise, which is a second reaction produced bythe generation of steam. This second reaction results" in a furthersaponification involving all mass of soap is in a very high globularstate, that is to say, a state of which state each fat molecule must bepositively saponified. During this stage, the stirring apparatuscontinuously operates and is stopped only after a uniformly homogeneousmass is obtained.

' correct, produces pink color.

This occupies about five to seven minutes.

The soap mass is now tested for its alkalinity, which will be absolutelycorrect when all the eonstituents have been carefully weighed. A smallamount of the cooled soap is moistened with phenol-phthalein solution,which, if the alkalinity is In the absence of said color, some alkali ismissing. In that case,

. fifty grams of flaky soda are dissolved in 100 filled. At this stage,the

the fat molecules, since the highest surface tension, in

not yet appear, further additions of the solution Just referred to aremade, until the mass shows the proper alkalinity.

If,on the other hand, the alkalinity should be too great shown bydark-red color upon moistening with phenol-phthalein, the alkalinitymust be reduced by the addition to the mass of cocoanut oil. By the slowadmixture of 250 to 500 grams of cocoanut oil and stirring of the mass,the excess of alkalinity is. corrected, which requires stirring from tento fifteen minutes depending on the amount of the soap mass.

Only after the saponification has been entirely completed, parafline isadded, for a premature addition of parafline would lead to a seriousdisturbance. of the saponification process. The hot parafline is slowlyadded at various places while the mass is being continually stirred,resulting in a quick distribution of the paraffine in the mass. At theend of the entire process stirring of the mass is once more efiected forsix to ten minutes. Because of the absorption of air during this laststirring operation, the volume of the mass increases somewhat, but themass becomes thicker and more creamy. After the process has beenfinished, the temperature will be about 90 to 92 C. The soap is nowtaken out of the kettle and passed over a system of cooling rolls.

I claim:

In the manufacture of soaps having a controlled alkalinity by coldprocessing, said soap producing a pink color. when moistened withphenol-phthalein solution, the improvement which comprises mixingtogether 200 parts of beef tallow and 50 parts of cocoanut oil, heatingthe mixture to between 50 and 52 C., stirring the hot mixture and adding1.2 parts of hydrogen peroxide solution, continuing the stirring andadding a preheated caustic soda solution, said solution being obtainedby dissolving 38.65 parts of flake caustic soda in 40 parts of water andhaving a temperature of 90 to 92 C., discontinuing the stirring upon thethickening of the \emulsion and causing the spontaneous reaction toproceed with the simultaneous generation of heat until substantiallycomplete, the generated heat bringing the soap mixture to about 120 C.and the hot mixture being intermittently stirred to control thereaction, again stirring the mixture after the exothermic reaction hassubsided and adding to the hot soap mixture at preheated alkalineaqueous solution of silicate, said solution of silicate being obtainedby mixing together 8 parts of water, 5 parts of silicate and 1 part of acaustic soda solution of the strength employed for saponification andheating the silicate mixture to 90 C., the said silicate solution beinggradually added and the stirring being continued until the soap mixturehas the desired alkalinity, and recovering the soap so produced.

. JULIUS SCHAAL.

